Treatment of hydrocarbon oils



Dec. 24,1935. J. D. SEGUY 2,025,532

' TREATMENT OF HYDROCARBON OILS I I Filed March 24, 1932 FRACTIONATOR CONDENSER REFRIGERATING OR COOLING COIL INVENTOR JEAN DELATTRE 'SEGUY.

Patented Dec. 24, 1935 PATENT} OFFICE 2,025,532 TREATMENT OF HYDROCARBON OILS Jean Delattre Seguy, Chicago, Ill., assignor to Universal Oil Products Company, Chicago, 11]., a corporation of South Dakota Application March 24, 1932, Serial No. 600,842

4 Claims. (Cl. 196-49) This invention relates more particularly to the conversion of liqueflable components separated from so called uncondensable gases resulting from cracking of hydrocarbon oil for the purpose --of producing fixed gas andvmore stable liquid products. 4

In the type of cracking operation where distillate and gas from the i'ractionator oi the system, are collected at substantiallyatmospheric 16"- or low superatmospheric pressure, the so called uncondensable gas will contain appreciable amounts oi liqueflable components which may be recovered by further cooling or refrigeration v and/or compression. These condensable hydrocarbons may comprise principally propane, methane, and their corresponding unsaturates as well as butane, pentane and in many cases-appreciable quantities oi hexane. Also, a portion of some or the heavier hydrocarbons normally contained within the distillate will not be condensed by the methods ordinarily employed and will remain entrained in the gases.

The present invention is particularly concerned with the treatment of this type of material, which may be separated from the gaseous products resulting from the conversion of hydrocarbon oils.

It is well known that cracking or pyrolytic conversion produces materials both lighter and heavier than the charging stock and it is also well recognized that relatively high temperature vaper-phase cracking is ordinarily accompanied by polymerization reactions. I have found that by subjecting the liqueflable components of gases resulting from cracking to suitable conditions of reconversion and commingling the resulting prodnets with the total products of the same cracking reaction in which the materials subjected to retreatment, were formed, the final products will show increased recovery of desirable light liquid products and a somewhat increased volume of fixed gas. It ismy belief that a portion of the increased liquid recovery may be accounted for by polymerization during retreatment of the condensables recovered from the gas and, in part,

4 by the action of the products of such retreatment upon the higher .boiling products of the cracking reaction.

The attached diagrammatic drawing illustrates one specific form of apparatus wherein the proc- 5 ess of the present invention may be practiced.

Raw oil charging stock for the system may be supplied through line and valve 2 to pump 3 from which it may be fed through line 4 and valve Iinto fractionator 6, serving the purpose of partially cooling and assisting fractionation of the vapors in this zone and being thereby preheated. The preheated raw oiLcharging stock, together with-reflux condensate comprising the relatively heavy components of the vapors condensed by fractionation is withdrawn from the lower por- 5 tion of the Iractionator through line i and valve 8 to pump 9 from which it is fed through line l0 and valve II to heating element I2 for conversion. When desired, aportion or all of the raw oil instead oi. passing overhead to fraction- 10 ator 6 may be directed from pump 3 through line l3 and valve it directly into line it and thence to heating element l2, together with reflux condensate from the iractionator.

Heating element I2 is located within a fur- 15 nace l5 oi any suitable form and the oil supplied thereto is heated to the desired conversion temperature, preferably at substantial superatmospheric pressure and is thence discharged ghrough line I6 and valve l1 into reaction cham- 2o Reaction chamber i8 is also preferably maintained at substantial superatmospheric pressure and in the particular case illustrated, this chamber is of the type wherein the vaporous conver- 2'5 sion products are subjected to continued conversion time while liquid products, which separate from the vapors and gravitate more rapidly to the bottom of the chamber, are subjected to conversion in this zone for a much shorter time than 30 the vapors. The total products, both liquid and vaporous, are withdrawn simultaneously from chamber I8 through line l9 and valve 20 and are introduced at reduced pressure into vaporizing chamber 2|. t 35 Reduced pressure chamber 2 I, in the case here illustrated, comprises the lower portion of fractionator 6, being separated from the fractionator by a suitable tray or deck 22 through which the vapors from chamber 2| may pass to the fraction- 40 ator and upon which reflux condensate from the fractionator may collect. It will be understood that the chamber 2| may, when desired, be a separate piece of equipment connected to the fractionator by a vapor-line, although this arrangement is not illustrated in-the drawing. Residual liquid remaining unvaporized in chamber 2| may be removed therefrom through line 23 controlled by valve 24 to cooling and storage or to any desired further treatment or, whende- I sired, conditions may be so controlled in the vaporizing chamber that only substantially dry coke remains as the residual product 01 the system; in which case this product may accumulate within the chamber 2| to be removed therefrom shown) may be employed for the accumulation cooling coil 38 may be utilized in conjunction with of coke and may be operated either alternately or simultaneously.

Vapors from the chamber 2| pass through the vapor outlet 26 into the fractionator 6 wherein their relatively heavy components are condensed as reflux condensate, to be removed therefrom and subjected to further treatment, as already described. Fractionated vaporous products pass from the upper portion of fractionator 6 through line 26 and valve 21, are subjected to condensation and cooling in condenser 26, from which the condensed and uncondensed products pass through line 28 and valve 30 to be collected in receiver 3|. The condensed distillate may be withdrawn from receiver 3| through line 32 and valve 33. A portion of this product may, when desired, be recirculated, by well known means not shown, to the upper portion of fractionator 6 for the purpose of regulating the vapor outlet temperature from this zone and to assist fractionation.

Products remaining uncondensed in receiver 3| are withdrawn therefrom through line 34 and valve 36 to compressor 36, by means of which the pressure thereon is substantially increased for the purpose of liquefying their high boiling components. When desired, a refrigerating or or instead of compressor 36. When utilized in conjunction withthe compressor, products from the compressor pass through line 31 and thence through line 39 and valve 40 into the coil 36, immer'ging therefrom through line 4| and valve 42 back into line 31 and thence through valve 43 into the separator 44. When the cooling coil is not used, it may be by-passed by means of valve 46, in line 31. Means for by-passing compressor 36 are well known and not here illustrated. Final separation of liquid and gaseous products is effected in separator 44. The gases may be released therefrom through line 46 and valve 41. The separator is preferably maintained under the increased pressure generated by compressor 36 in order to prevent vaporization .of the liquefied products and in case. the refrigerating or cooling coil is used, separator 44 and the connecting lines may be heavily insulated.

, The liquefied components of the uncondensed products from receiver 3| which accumulate in separator 44, are withdrawn therefrom through line 46 and valve 49 to pump by means of which they may be supplied through line 6| and valve 62 to a separate heating element 63 wherein they are subjected, by means of heat supplied from furnace 64, ofanysuitable form, to a conversion temperature of the order of about 1200 to 1600 E, at a pressure which may range from about to 1000 pounds. or more, per square inch.

A separate reaction zone 66 may be provided to permit continued conversion of the heated materials, in which case the heated materials from heating element 63 pass through line 66, line 61, valve 68, reaction chamber and are withdrawn therefrom through line 69, passing through valves 66 and 6| into line l6 and thence to vaporizing chamber 3|. When it is not desired to use reaction chamber 66, it may be by-passed by closing valves 68 and 66 and opening valve 62, in line 66, thus passing materials from heating element .1; 63 through line 66, valve 62, line 66, valve 6| and line I! direct-to vaporizing chamber 3|. It is a charging stock for the cracking operation is such that these same conditions give good results for its conversion, heating element 63 and reaction chamber 66 may be dispensed with and the liquell fled products from separator 44 may be supplied from pump 60 through line 6|, line 63 and valve 64 into line H), commingling therein with the other oils to be cracked and passing therewith to heating element H, for further conversion.

The heating element to which the raw oil. charging stock and reflux condensate from thefractionator are supplied may utilize conversion temperatures ranging, for example, from 875 to 1050 F. with superatmospheric pressures of the 35 order of 100 to 800 pounds, or more, per square inch in this heating element and the succeeding reaction chamber, the vaporizing, fractionating, condensing and collecting portions of the system preferably utilize relatively low pressure of the order of 100 pounds or thereabouts down to substantially atmospheric premure. Substantial superatmospheric pressure up to several hundred pounds per square inch is, however, preferably employed in the separator to which the compressed and/or cooled gases from the receiver are directed. As previously mentioned, temperatures in the heating element to which the liquefied components of the gases are supplied, may range from 1200 to 1600 F., orthereabouts with a pressure in this zone and in the succeeding reaction chamber, when the latter is used, ranging preferably from 100 to 1000 pounds, or more, per square inch.- a V To more clearly illustrate thefeatures and advantages of the process, let us first consider a cracking operation not utilizing the present invention. The raw oil charging stock is a Mid- Continent topped crude of about 31 A. P. I. new 0 ity which is subjected, together with reflux condensate from the fractlonator of the system, to a temperature in the heating element of about 920 F. The heating element and reaction chamber are maintained at asuperatmospheric pressure of approximately 350 pounds per square inch. The vaporizing chamber and succeeding portions of the system are maintained at a substantially equalized pressure of approximately 60 pounds per square inch. This operation may re- .9 sult in the production of about 64%, based on the raw oil, of 400 F., end point motor fuel having an octane number of approximately 68, about 27% of residual oil, the remaining 9% based on the charging stock being chargeable to gas, loss I I and a small percentage of coke.

When theabove operation is modified by the incorporation of the features of the present invention, gas from the receiver of the system is compressed under a pressure of about 600 pounds 10 porizing chamber of the cracking system. By this method the yield of motor fuel may be increased to approximately 72% of the charging stock and may have an anti-knock value equivalent to an octane number of approximately 75. The residual oil is reduced to coke, which may amount to approximately 50 pounds per barrel of charging stock and the yield of gas is substantially increased.

In another type of operation carried out in accordance with the present invention, the raw oil charging stockis a Pennsylvania straight-run gasoline containing a naphtha fraction boiling up to approximately 500 F. which is subjected, in the heating element, to a temperature of about 950 F. under a superatmospheric pressure of approximately 800 pounds per square inch. Substantially this same pressure is maintained in the reactionchamber, which is reduced in the vaporizing chamber to approximately 50 pounds per square inch, and substantially equalized in the succeeding fractionator, condenser and receiver. The heavy components of the gas are subjected to liquefaction under about the same conditions as mentioned above and the recovered liquid is returned to the same heating element to which .the charging stock and reflux condensate are supplied. This operation may yield, based on the charging stock, about of motor fuel having an octane number of approximately 80, the remaining products being gas and a small amount of coke.

I claim as my invention:

1. In a process for the conversion of hydrocarbon oil wherein the oil is subjected to con-.-

version conditions of elevated temperature and superatmospheric pressure in a heating coil and reaction chamber and thereafter discharged into a reduced pressure chamber where vapors separate from non-vaporous residue, the vapors being subjected to fractionation followed by condensation and collection of resulting distillate and uncondensed products, the improvement which comprises subjecting the latter, following their separation from thedistillate, to liquefaction to effect the removal of their high boiling components, subjecting the recovered liquid to further conversion at a higher temperature than that employed in the, first mentioned heating coil and introducing said heated. liquid into the reduced pressure chamber. v

2. A process for the conversion of hydrocarbon oils to produce maximum yields of motor fuel of good anti-knock characteristics which comprises subjecting the oil to conversion conditions of elevated temperature, and superatmospheric pressure in a heating element, introducing the heated material into a reaction chamber, withdrawing the total products from the reaction chamber and subjecting them to vaporization'at reduced pressure in a vaporizing chamber, sub- 5 jecting the vapors to fractionation, subjecting the fractionated vapors to condensation, collecting the resulting distillate and uncondensed products, liquefying and separating from the latter their high boiling components, subjecting the re- 10 covered liquid to further conversion at a temperature higher than that employed in the first mentioned heating element, and introducing them into'the vaporizing chamber.

3. A process for the conversion of hydrocarbon 15 oils to produce maximum yields of motor fuel of good anti-knock characteristics which comprises subjecting the oil to conversion conditions of elevated temperature and super-atmospheric pressure in a heating element, introducing the heated 20 material into a reaction chamber, withdrawing the total products from the reaction chamber and subjecting them to vaporization at, reduced pressure in a vaporizing chamber, subjecting the vapors to frictionation, returning the heavy com- 25 ponents of the vapors condensed by fractionation tion zone and thence introducing them into the vaporizing chamber.

4. A conversion process which comprises subjecting hydrocarbon oil in a cracking zone to 40 cracking temperature under suflicient pressure to maintain a substantial portion thereof in liquid phase, discharging the cracked oil into a separating zone maintained under lower pressure than the cracking zone and separating the same 45 therein into vapors and residue, fractionating and then finally condensing the vapors and separating resultant condensate from unconden'sed gases, separating higher boiling components from the uncondensed gases and subjecting the same 505 in an independent conversion zone to higher conversion temperature than the oil in the first" named zone, and then introducing the thus treated higher boiling components into said separating 55 zone.

JEAN DELATI'RE SEGUY. 

